Rapid identification technology of invasive filamentous fungi by MALDI-TOF MS

Abstract

Abstract: Objective To evaluate the application value of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) technology in the identification of clinical common filamentous fungi in clinical practice. Methods From April 2017 to July 2019, 65 filamentous fungi were isolated and cultured from various types of clinical specimens of ourhospital and 26 common filamentous fungi donated by a large third-class hospital. After the 91 filamentous fungi were identified by traditional morphological identification, DNA sequencing and MALDI-TOF MS, the results of DNA sequencing were compared with those of the other two methods to evaluate the application of MALDI-TOF MS in the identification of clinical filamentous fungi. Results The filamentous fungi cultured at 28℃ and 35℃ were identified by mass spectrometer, the Chi-square test(χ² test,P=0.05) showed that P>0.05, suggesting that there was no significant difference in culture temperature between the two groups.Using DNA sequencing results as gold standard, the correct identification rate of traditional morphological methods was 81.3% (74/91), while that of MALDI-TOF MS technology was 97.8% (89/91). In this study, the correct identification rate of filamentous fungi by mass spectrometry was 90.1% (82/91) after extracting protein by acetonitrile formate extraction method, while that of protein extracted by magnetic bead grinding method was 97.8%(89/91). Conclusion In clinical routine work, when using mass spectrometer to identify common filamentous fungi, the culture temperature will not affect the mass spectrometry identification results; the correctness of mass spectrometry after improved magnetic bead grinding method to extract protein is better than that recommended by mass spectrometer to extract acetonitrile formate; compared with traditional morphological identification, MALDI-TOF MS technology is faster, more objective, more efficient and more accurate in identification of common filamentous fungi.

Key words: MALDI-TOF MS, filamentous fungi, rapid identification

CLC Number:

ZHANG Jing, JIANG Bin, PENG Na, OUYANG Pengwen, Xu Wen, Ning Xingwang, LIU Qiong, XIE Liangyi. Rapid identification technology of invasive filamentous fungi by MALDI-TOF MS[J]. Chinese Journal of Mycology, 2021, 16(4): 247-251.

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